In the Syrian form of this liturgy, after the Words of Institution, to which the people respond with "Amen" after the formula for the blessing of the bread and again after the formula for the blessing of the chalice, the priest celebrant says: "Do in remembrance of Me when you partake of this sacrament, commemorating My death and My resurrection until I come." The people then respond with the acclamation: "Your death, our Lord, we commemorate, Your resurrection we confess and Your second coming we wait for. May Your mercy be upon us all."[2]

In the Byzantine form of the Liturgy of St James, the priest celebrant says: "This do in remembrance of me; for as often as ye eat this bread, and drink this cup, ye do show forth the Lord's death, and confess His resurrection, till He come." The people respond: "We show forth Thy death, O Lord, and confess Thy resurrection."[3]

As a lead to the Memorial Acclamation, the priest says or sings: "The mystery of faith".[5]

This introductory phrase, mysterium fidei in the Latin original, was previously translated loosely into English as "Let us proclaim the mystery of faith", and in some places was sung or spoken by the deacon instead of the priest in spite of the clear instruction in the Missal itself and in the apostolic constitution Missale Romanum with which Pope Paul VI promulgated the revision of the Roman Missal.[6] The English translation was corrected in 2011 and now reads simply: "The mystery of faith".

Before the 1969 revision of the Roman Missal, the phrase mysterium fidei was included in the formula of consecration of the wine spoken inaudibly by the priest,[6] appearing as follows (here accompanied by an unofficial English translation):[7]

Text (in Latin)

Simili modo postquam cenatum est,

accipiens et hunc praeclarum calicem

in sanctas ac venerabiles manus suas:

item tibi gratias agens, benedixit,

deditque discipulis suis, dicens:

Accipite, et bibite ex eo omnes.

Hic est enim calix sanguinis mei,

novi et aeterni testamenti:

mysterium fidei:

qui pro vobis et pro multis effundetur

in remissionem peccatorum.

Haec quotiescumque feceritis,

in mei memoriam facietis.

Unofficial English translation

In like manner, after He had supped,

taking also into His holy and venerable hands

this goodly chalice,

again giving thanks to Thee, He blessed it,

and gave it to His disciples, saying:

Take and drink ye all of this:

For this is the chalice of My blood,

of the new and eternal testament:

the mystery of faith:

which will be shed for you and for many

unto the remission of sins.

As often as ye shall do these things,

ye shall do them in remembrance of me.

After the revision, the text and the official English translation are now as follows:

Text (in Latin)

Simili modo postquam cenatum est,

accipiens et hunc praeclarum calicem

in sanctas ac venerabiles manus suas,

item tibi gratias agens benedixit,

deditque discipulis suis, dicens:

Accipite, et bibite ex eo omnes:

hic est enim calix Sanguinis mei

novi et aeterni testamenti,

qui pro vobis et pro multis effundetur

in remissionem peccatorum.

Hoc facite in meam commemorationem.

Mysterium fidei.

Official English translation

In a similar way, when supper was ended,

he took this precious chalice

in his holy and venerable hands,

and once more giving you thanks, he said the blessing

and gave the cup to his disciples, saying:

Take this, all of you, and drink from it,

for this is the chalice of my Blood,

the Blood of the new and eternal covenant,

which will be poured out for you and for many

for the forgiveness of sins.

Do this in memory of me.

The mystery of faith.

Some traditionalist Catholics criticized the removal of the phrase mysterium fidei from the words of consecration,[8] even claiming that it made the Mass invalid.[9]

The phrase mysterium fidei was added to the words of consecration at some time before the 6th century, perhaps by Pope Leo I (440-461) and perhaps, in reaction to the denial by Manichaeism of the goodness of material things, as an expression of the Catholic Church's belief that salvation comes through Christ's material blood and through participation in the sacrament, which makes use of a material element.[10]

The memorial acclamations that follow suggest that "the mystery of faith" refers, in its new context, to "the entire mystery of salvation through Christ's death, resurrection and ascension, which is made present in the celebration of the Eucharist". An alternative memorial acclamation permitted in Ireland, "My Lord and my God", was disapproved of by Pope Paul VI for seemingly concentrating on the real presence of Christ in the Eucharist rather than on Eucharistic sacrifice as a whole, but even this may be interpreted in the same sense, since it is a repetition of what in John 20:28 refers to Christ as risen and as still bearing the marks of his suffering.[10]

^Rama P. Coomaraswamy The destruction of the Christian tradition 2006 p279 "Not only is this an entirely new practice, but it implies that the Mystery of the Faith is the Death, Resurrection, and Final Coming of Our Lord, rather than His 'Real Presence' on the altar."